08:48 Jan 27, 2009 

Thanks for that context, it makes things much clearer. I don't know about US usage but for large-scale structures of the type you describe the UK dept of agriculture prefers "glasshouse" over "greenhouse" except in the specific case of "greenhouse gases" or "greenhouse effect"

08:35 Jan 27, 2009 

Sorry for the lack of context. I'm still getting the hang of posting questions and I err on the side of wanting to be concise. Here is some context for you to sink your teeth into:

"Public attitude towards the development of greenhouse clusters in Flanders

In recent years the agricultural sector has been confronted with several structural changes, including an increase in scale. In other leading horticultural countries such as the Netherlands and Spain, new commercial greenhouses are almost exclusively larger than 3 ha and may stretch over 30 ha in a single development (Badgery-Parker, 2001). If the Flemish horticulture sector wants to maintain or even strengthen its position on (inter)national markets, increase in scale and modernisation of the existing greenhouses will be essential."

Later in the article, they suddenly decide to use the word 'glasshouse' which I changed to 'greenhouse' in order to keep it consistent with the above usage.

Thus you see, this question is about very large, horticultural businesses and not something attached to a house nor in someone's back garden. In America, a greenhouse can be small or large, but is always a separate building; the term 'glasshouse' is not familiar to me. Hence my question. Thanks already for the feedback provided, it has already been useful but a definite-definite answer would be ideal of course.

17:35 Jan 26, 2009 

Could you give us some more information (such as exact source language) and a bit more context here, please? We're all trying to help you, but you're kind of leaving us hanging in the dark here.